Safety guard for grinding machine



Dec. 18, 1962 B. TOCCl-GUILBERT SAFETY GUARD FOR GRINDING MACHINE Filed Feb. 6, 1961 uvmvron Berna Tocci-Guilbert Y 071% @Qm Attorneys United States Patent f This invention relates to a safety guard for grinding machines and more particularly to safety guards for portable grinding machines which are held in engagement with the work piece by the operators hands.

In general, safety devices heretofore provided for portable grindng machines have not been completely satisfactory. They have been diflicult to mount on the machine and, in addition, they have been diflicult to hold in a predetermined position on the machine. There is, therefore, a need for a new and improved safety guard for grinding machines.

In general, it is an object of the present invention to provide a safety guard for grinding machines which overcomes the above named disadvantages.

Another object of the invention is to provide a safety guard of the above character which is readily adjustable.

Another object of the invention is to provide a safety guard of the above character which is particularly adapted for use with angle head motors.

Another object of the invention is to provide a safety guard of the above character which is provided with additional means for positioning the guard and maintaining it in a predetermned position.

Another object of the invention is to provide a safety guard of the above character which can be readily attached to and detached from the grinding machine.

Additional objects and features of the invention will appear from the following description in which the preferred embodiment is set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

FIGURE 1 is a perspective view of my safety guard .mounted on a grinding machine.

FIGURE 2 is a plan view of my safety guard.

FIGURE 3 is a side elevational view of my safety guard with certain portions in corss-section.

In general, my safety guard is adapted for use with a grinding machine of the type having a housing, a motor mounted in the housing, and an abrasive disc driven by the motor. The safety guard comprises a shield member in the form of a ring segment having an outer peripheral wall. Means is provided for securing the shield member to the housing to support the shield member in a position so that the peripheral wall of the ring segment extends through the plane of rotation of the abrasive disc. The safety guard also includes additional means mounted on the shield member and engaging the housing to maintain the shield member in a predetermined position with respect to the abrasive disc.

My safety guard 19, as shown in FIGURE 1 in phantom lines, is mounted on a portable grinding machine 11. This portable grinding machine 11 is of a type well known to those skilled in the art and consists of a housing 12 comprised of two parts 12a and 12b. The portion 12a of the housing encloses an electric motor (not shown), whereas the portion 12b encloses a gear reduction unit (not shown) as is well known to those skilled in the art. The portion 12b of the housing 12 is provided with an additional cylindrical portion 120 which normally is called the spindle bearing housing collar. The grinding machine is also provided with handles 13 and 14 which are grasped by the operator in operating the grinding machine in a manner well known to those skilled in the art.

3,068,620 Patented Dec. 18, 1962 The grinding machine 11 also includes an abrasive disc 16 of a suitable type such as a depressed center or raised hub disc secured to the output shaft (not shown) of the grinding machine by suitable means such as a resilient coupling 17. The resilient coupling 17 can be of any suitable type.

My safety guard consists of a shield member 21 in the form of a sheet steel piece formed as a ring segment subtending approximately The shield member consists of an outer peripheral substantially vertical wall portion 21a which is provided with an inwardly turned terminal lip 22 on its lower extremity. The shield member also consists of a flat circular portion 2112 which joints the portion 21a at substantially right angles. The inner terminal portion of the flat portion 21b is provided with a downwardly turned terminal lip 23. Although the shield member has been shown subtending approximately 120, if desired, it can extend over a lesser or greater angle. As is well known to those skilled in the art, it is desirable that the shield member 21 should permit full utilization of the abrasive disc 15, while at the same time providing adequate safety. v

The shield member 21 is provided with a plurality of slots 26 in its upper fiat wall portion 21b which are arranged in pairs extending in different angular directions for a purpose hereinafter described.

Means is provided for attaching the shield member to the grinding machine and consists of an angle foot member 31 and a pair of collar members 32 and 33. The angle foot member is provided with a horizontal portion 31a which is secured to the shield member by suitable means such as bolts 36 extending through the portion 31a and mounted in the slots 26 provided in the shield member 21. The angle foot member 31 is provided with a vertical portion 31b which extends at right angles to the portion 31a. The collar member 32 is provided with a vertical portion 32a which is seated against the portion 31b of the angle foot member 31 and is adapted to be adjusted vertically with respect thereto. The means permitting vertical adjustment consists of a pair of bolts 37 which extend through elongate slots38 provided in the portion 32a and slots 39 provided in the portion 31b.

The collar member 32 is also provided with a horizontal portion 32b which extends at right angles to the portion 32a and lies in a plane generally parallel to the flat portion 21b of the shield member. The collar member '32 is provided with an upwardly turned flange portion 320 on the terminal end of the portion 3211 which is formed to provide a substantially semicircular recess 41 which is adapted to seat against the spindle bearing housing collar 12a of the grinding machine. The collar member 33 is provided with a portion 33a which lies in substantially the same plane as the portion 32b of the collar member 32 and an upwardly extending flange portion 3312 on the inward terminal portion of the portion 33a and is formed to provide a substantially semi-circular recess 42 which is adapted to engage the other side of the spindle bearing housing collar 12c.

Means is provided for releasably fastening the collar members 32 and 33 to the spindle bearing housing collar 12c and consists of bolts 44 provided in the flange portions 320 and 33b of the collar members 32 and 33 as shown partcularly in FIGURE 2.

In securing the collar members 32 and- 33 to the spindle bearing housing collar, it may be desirable in order to adapt the collar member to different sizes of spindle bearing housing collars, to provide shim members 48 of suitable material such as plastic or rubber mounted within the recesses 4-1 and 42 of the collar members as shown to ensure that the collar members 32 and 33 will firmly engage the spindle bearing housing .adapted for use with grinding machines.

3 collar of the grinding machine and to thereby hold the shield member 21 in the desired position. The shim members 48 also serve to shock mount the guard.

The bolts 37 in cooperation wth the slots 38 and 39 provided in the members'fil and 32 permit vertical adjustment of the shield member so that the outer peripheral wall 21 is disposed so that it intersectsor passes through the plane of rotation of the abrasive disc 16. It is readily apparent that it is desirable to position the shield member 21 inthis manner so as to protect the operator in the event that the abrasive disc 16 should shutter or break for any reason.

Additional means is provided for maintaining the shield member 21 in the desired position with respect to the abrasive disc 16 and consists of an extension 3710 which is provided on the member 31. The extension 31c lies in the same plane as the portion 31b and extends up above the portion 32b of the collar member 32. This extension 31c is provided with a recess 51 formed in a particular manner so that it engages the housing 11 .of the grinding machine when the shield member 21 is in the proper position The positioning of the recess 46 to accomplish this purpose is shown particularly in FIG- URE I. The recess is formed so that it will conform to the contours of the portion of the housing 11 which it engages.

It can be readily seen from FIGURE 1 that the exten sion 310 provides an additional support for the shield member 21 to maintain it in a predetermined position. .It is also readily apparent that the shield member 21 will be maintained in this predetermined position even though the shield member 21 should accidentally be lowered into engagement with the work piece. This additional extension 31c, therefore, ensures that the shield member 21 will always be in the proper position to provide the maximum protection for the operator of the machine.

As explained in my Patent No. 2,819,570, the slots 26 make it possible to shift the shield member 21 between two extreme positions as shown by the dot and dash lines in FIGURE 2 to accommodate right and left-hand operators.

It is apparent from the foregoing that I have provided a new and improved safety guard which is particularly The safety guard is constructed in such a manner that it can be readily attached to and detached from the grinding ma chine merely by tightening and'loosening the bolts 44. The collar members 32 and 33 can be readily positioned with respect to the shield member 21 by means of the .bolts 37 so that the shield member is always in the proper vertical position to provide the maximum protection to the operator of the grinding machine.

I claim:

*1. In a safety guard adapted for use with a grinding machine of the type having a housing, a motor mounted within the housing, and an abrasive disc driven by the moextending through the plane of rotation of the abrasive disc, means for securing the shield member to the housing to support the shield member in a position so that the peripheral wall of the ring segment extends through the plane of rotation of the abrasive disc, and additional means mounted on the shield member and engaging the housing of the grinding machine to maintain the shield member in a predetermined position with respect to the abrasive disc.

2. A safety guard as in claim 1 wherein said means for securing the shield member to the housing consists of a pair of separate collar members, and means for clamping the collar members together to fasten them to the housing, and wherein said additional means engaging the housing at a point spaced from said first named means includes a member engaging the housing.

3. In a safety guard adapted for use with a grinding machine of the type having a housing, a motor mounted Within the housing, an abrasive disc driven by the motor, the safety guard comprising a shield member in the form of a ring segment having an outer peripheral wall, a member secured to the shield and engaging the housing, and means mounted on said last named member and engaging the housing at a point spaced from the point at which said first named means engages the housing, said first named means and said last named means serving to position the shield member so that the outer peripheral wall extends through the plane of rotation ofthe abrasive disc.

4. A safety guard as in claim 3 together with means permitting adjustment of the position of said last named means with respect to the first named means engaging the housing. 5. In a safety guard adapted for use with a grinding machine of the type having a housing, a motor mounted within the housing, an abrasive disc driven by the motor, the housing having a. collar having an axis substantially coincident with the axis of rotation of the abrasive disc, the safety guard comprising a shield member in the form of a ring segment having an outer peripheral Wall, a foot member secured to the shield member, a pair of collar members, means for fastening the collar members to the portion of the housing having an axis substantially coincident with the axis of rotation of the abrasive disc, and adjustable means for securing one of said collar members to said foot member secured to the shield member to permit adjustment of the position of the collar members with respect to the foot member, said foot member having a portion engaging the housing at a point spaced from the collar members.

6. A safety guard as in claim 5 together with resilient 'means mounted between the collar members and the portion of the housing having an axis substantially coincident with the axis of rotation of the abrasive disc to provide a shock mounting for the safety guard.

References Cited in the file of this patent UNITED STATES PATENTS 2,819,570 Tocci-Guilbert Ian. 14, 1958 

